Unit ventilator grille arrangement



May 24, 1966 N. E. HORST ET L UNIT VENTILATOR GRILLE ARRANGEMENT Filed Oct. 30, 1963 FIG.2

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INVENTORS NORMAN E. HORST BERNARD J. LAVINS ATTORNEY United States Patent 3,252,397 UNIT VENTILATOR GRILLE ARRANGEMENT Norman E. Horst, Moline, Ill., and Bernard J. Lavins,

Bettendorf, Iowa, assignors to American Air Filter Company, Inc., Louisville, Ky., a corporation of Delaware Filed Oct. 30, 1963, Ser. No. 320,039 4 Claims. (Cl. 98--40) This invention relates to a unit ventilator grille arrangement.

Among the objects of the invention is the provision of a unit ventilator grille arrangement which not only affords substantial manufacturing economy but also admirably meets the appearance and safety demands peculiar to a unit ventilator grille arrangement.

These objects are satisfied in accordance with the invention by providing a unit ventilator cabinet grille arrangement which includes: a one-piece grille, fabricated of relatively inexpensive steel members, extending for the length of the cabinet top wall opening overlying the center and end compartments; hinge means for one edge of the grille; means for latching the grille in its normal operational position; and, spring means urging the grille to a readily observable open position when the latch means are released.

One currently preferred embodiment of the invention will be described in connection with the accompanying drawing wherein:

FIGURE 1 is an isometric view of a unit ventilator having a grille arrangement according to the invention;

FIGURE 2 is an isometric view of a unit ventilator with the grille in a fully open position affording access to the top of the center and end compartments of the unit ventilator;

FIGURE 3 is a vertical sectional view of the grille corresponding to one taken along the line 3--3 of FIG- URE 2;

FIGURE 4 is a fragmentary end view of the unit ventilator showing the grille in an intermediate open position to which it is urged by the spring means when the grille is unlatched; and

FIGURE 5 is a fragmentary isometric view of a spring arrangement for the grille.

The unit ventilator cabinet of FIGURE 1 includes a front wall panel 10, end wall panels 12, and a solid top wall 14 extending along the rear portion of the top of the cabinet. The forward portion of the top of the cabinet is an essentially open area covered by the grille 16. The unit ventilator is usually mounted so that the unfinished back wall (not shown) abuts the room wall with an opening in the back wall aligned with a louvered outdoor air opening in the room wall to permit controlled quantities of outdoor air to be introduced into the unit ventilator. Recirculating room air typically is introduced through a grille covered opening 18 into the lower front part of the unit ventilator for mixing with whatever quantity of outdoor air is introduced.

The typical unit ventilator has its interior divided into a center compartment 20 (FIG. 2), and a pair of opposite end compartments 22 and 24 by vertical partitions 26 and 28 respectively. The center compartment contains fans, coil, and dampers, which respectively move, heat or cool, and control, the air which the unit ventilator handles.

In the version shown, the fans are mounted immediately below the top wall 14 with their outlets 30 immediately below the area covered by the center part of the grille 16. In some unit ventilators the positions of the coil and fans are reversed so that a so-called blow-through arrangement is provided in which the coil is immediately below the grille 16 and the fans are located farther down in the center compartment of the unit ventilator.

The separate end compartments usually house, among other things, the control elements which actuate the air flow dampers, piping and valves, and fan motors and switches therefor, and are normally covered at the top so that uncontrolled air does not pass through the end compartments and thus bypass the center compartment.

In accordance with the invention, the grille 16 extends in unbroken fashion for the length of the cabinet as an integral, one-piece assembly. The grille is fabricated of a number of long, thin steel bars 32 and a series of cross rods 34 underlying the bars to tie them together. The

bars are arranged, as shown in FIG. 3, to extend in parallel spaced relation with each bar being tilted slightly from a vertical plane. Each intersection of a bar and rod is welded so that a rather strong one-piece assembly results. In the preferred assembly, the cross rods 34 are grooved to receive the lower edges of the bars 32.

The end portions of the grille which overlie the end compartments when the grille is in a closed position are provided with block-ofr plates 36 (FIG. 2) to close the tops of the end compartments. The illustrated version of the grille also includes narrow strips 38 extending along the bottom surface of the grille parallel to the cross rods 34 to block off the space between adjacent edges of adjacent fan housing outlets 30. The block-off plates 36 and strips 38 are also welded to the bars 32 during the fabrication process. The resultant grille is a strong, relatively rigid structure.

A hinge 40 is provided near each end of the grille, and at the center on relatively long grilles, to hingedly secure the rear edge of the grille to the forward edge of the stationary top wall 14. Latch means 42, located at the forward edge of each of the block-off plates 36, engage keepers disposed immediately behind the upper front molding 44 in each of the end compartments. The latches may be of any suitable form but preferably are rotatable only with a special tool to prevent casual unlatching.

An essential feature of the invention is the spring arrangement biasing the grille toward a readily observable open position (FIG. 4) when the latches are released. One suitable form of spring means is shown in FIG. 5 wherein a spring steel rod is bent so that in its unstressed condition its one end 46 extends under the top wall 14, the intermediate part 48 extends along the forward edge of the top wall 14 with clips 50 holding it in this position, and the other end or arm 52 extends upwardly and terminates in a loop 54. When .the grille is swung downwardly from a fully open position to a closed poistion, the undersurface of the block-off plates engage the loops 54 and arms 52 and apply a torsional force to the intermediate part 48 of the spring. In a closed position of the grille, the spring lies as a whole in a substantially horizontal plane with the arm 52 and loop 54 bearing upwardly against the undersurface of the blockoif plate 36. When the latches are released so that the grille may be opened, the grille is forced upwardly to a' balanced position as shown in FIG. 4, wherein the weight of the grille pressing downwardly equals the upward force of the springs.

The described grille arrangement for a unit ventilator provides some advantages which may not be readily apparent without certain background explanation. Unit ventilators are used in classrooms of primary and elementary schools more than in any other environment. As such, they are occasionally subject to some tampering or experimentation by students. Hence it is usual that an attempt be made to make the unit ventilators childproof. One aspect of child-proofing the units is to deny access to those interior parts of the unit which are capable of being damaged by the children, and which in turn are capable of injuring the children. For example, it is not unknown for children to attempt to stick their fingers into rotating fans if they have access to the fans.

At the same time, since the unit ventilators include a considerable number of parts which require some attention for proper operation and maintenance, the need of child-proofing must be balanced against providing reasonable ease of access to those interior parts requiring occasional attention. Some of these parts, such as fan motor speed and on-oif switches, are normally grouped in an end compartment with the preferred access being had from the top of the cabinet. Thus a common past practice has been to provide a grille which permits separate access to each end compartment. Typically the end compartment top doors were hinged and a latch was provided to lock the end compartment top doors in place. In the event a child discovered that an end compartment access door was unlatched, and the child thus gained access to the end compartment, the worst that could be reasonably expected would be that the child would switch the fan motor to some other speed or tie-energize the fan motor. The removable portion of the top wall which covered the fan outlets was usually secured somewhat more permanently so that it typically required some effort and one or more special tools to remove it.

As styling has become a more important consideration in unit ventilator manufacture, there has been a trend to a design which has a rectangular aspect and includes lines extending for the length of the unit ventilator in unbroken fashion. Additionally, the grille has been emphasized as a distinctive feature which contributes to the design rather than detracts from it. Thus to achieve the desired styling, at least one previous commercial version of a unit ventilator has utilized an extruded aluminum grille extending for the length of the cabinet, but divided into separate sections for the tops of the end compartments and the center compartment. The previous practice of making the end compartments more accessible than the center compartment from the top of the cabinet was followed in this particular commercial version of a unit ventilator and to gain access to the top of the fan outlets it was necessary to loosen the upper front molding; a formidable task for a youngster without the proper tools.

A fabricated steel grille of the nature previously described (i.e., according to this invention) is substantially less expensive than an extruded aluminum grille of the same size. Further, the fabricated steel grille in one-piece form extending for the length of the cabinet is fully acceptable from a styling standpoint. However, the advantages of the low cost steel grille are lost if it is divided into separate sections in accordance with the compartmentalization of the unit ventilator cabinet since its rigidity is decreased, and additional hinges and/or fasten; ers are required. On the other hand, to use a one-piece grille for the lengt'h of the unit ventilator necessarily results in the center compartment top being opened each time access is had to the top of an end compartment. This poses a hazard from the standpoint of increasing the possibility that children can gain access to the fan wheels when they are rotating.

It is our view that previous grille arrangements have been susceptible to being left in an unlatched position because the custodian could not easily tell whether the grilles were latched or not when the grilles were in a closed position unless he actually tried to open the grille or alternatively closely inspected it.

If this view is correct, it will be appreciated that with the grille arrangement of the present invention the likelihood that the custodian would fail to see that the grille is unlatched, when the grille is in fact unlatched and is therefore in a readily observable unlatched position as shown in FIG. 4, is remote indeed. Further, even if the custodian were to fail to note that the grille Was in its spring biased open position, there is an exceedingly good chance that the teacher holding class in the room would observe the open position of the grille and keep the children away from the unit ventilator until the custodian could return to latch the grille.

It will thus be appreciated that with the arrangement according to the invention we offset the increased hazard due to the common access to the center compartment and the end compartments by reducing the chance that the grille will be left unlatched. Thus the difiiculties originally envisaged in using a one-piece grille are obviated by the invention and the low cost fabricated steel grille according to the description herein becomes particularly suitable for use. While such a grille, say in a six foot length, may be relatively heavy, the spring means biasing it toward an open position makes opening of the grille relatively easy since the springs effect the initial opening from a closed position when the grille is unlatched.

The invention claimed is:

1. In a unit ventilator:

(a) an exterior cabinet enclosing a center compartment and at least one end compartment, said cabinet having a top wall opening extending for substantially the length of said cabinet and overlying said center com partment and said end compartment;

(b) a one-piece grille member extending for the length of said top wall opening;

(c) hinge means pivotally connecting said grille mem-' her to said exterior cabinet along one edge of said grille member;

((1) means for latching said grille member in a closed position; and,

(e) spring means biasing said gr lle member to an intermediate open position which is readily observable upon release of said latch means.

2. In a unit ventilator:

(a) an exterior cabinet enclosing a center compartment and a pair of opposite end compartments separated by partitions from said center compartment, said cabinet including a top wall having an opening along its forward portion extending for substantially the length of said cabinet and overlying the tops of said center and said end compartments;

(b) a one-piece grille member extending for the length of said top wall opening;

(0) hinge means pivotally connecting said grille member to said exterior cabinet along one edge of said grille member;

(d) means for latching said grille member in a closed position; .and,

(e) spring means biasing said grille member to an intermediate open position which is readily observable upon release of said latch means.

3. In a unit ventilator as specified in claim 2:

(a) said grille member comprises a series of spaced, parallel steel bars having a length corresponding to the length of said cabinet, and a series of steel cross rods, forming an openwork structure.

4. In a unit ventilator as specified in claim 3:

(a) said grille member includes air block-off end plates connected to said bars to overlie sa d end compartments and blOCk-Ofi air flow therethrough.

References Cited by the Examiner UNITED STATES PATENTS 1,756,997 5/1930 Shurtleff 9840 2,681,000 6/1954 Redmond 98121 X 2,710,717 6/ 1955 Palmer 98-94 X 3,033,096 6/1962 Aitken '981 14 X 3,111,075 11/1963 Hoyle 98-40 WILLIAM F ODEA, Primary Examiner.

JOHN F. OCONNOR, Examiner. 

1. IN A UNIT VENTILATOR: (A) AN EXTERIOR CABINET ENCLOSING A CENTER COMPARTMENT AND AT LEAST ONE END COMPARTMENT, SAID CABINET HAVING A TOP WALL OPENING EXTENDING FOR SUBSTANTIALLY THE LENGTH OF SAID CABINET AND OVERLYING SAID CENTER COMPARTMENT AND SAID END COMPARTMENT; (B) A ONE-PIECE GRILLE MEMBER EXTENDING FOR THE LENGTH OF SAID TOP WALL OPENING; (C) HINGE MEANS PIVOTALLY CONNECTING SAID GRILLE MEMBER TO SAID EXTERIOR CABINET ALONG ONE EDGE OF SAID GRILLE MEMBER; (D) MEANS FOR LATCHING SAID GRILLE MEMBER IN A CLOSED POSITION; AND, (E) SPRING MEANS BIASING SAID GRILLE MEMBER TO AN INTERMEDIATE OPEN POSITION WHICH IS READILY OBSERVABLE UPON RELEASE OF SAID LATCH MEANS. 